Welt-guide for boot and shoe sewing machines.



M. T. DENNE.

WELT GUIDE FOR BOOT AND SHOE SEWING MACHINES.

APPLICATION FILED JULY 6,1914.

Patented Aug. 28, 1917. I

VViTnesses. Wanton MurkTDenne, 7&4, WWWGYW A Hy's MARK THOMAS DENNE, 0F 'RUSI-I DEN, ENGLAND.

WELT-GUIDE FOR BOOT AND SHOE SEWING MACHINES.

Specification of Letters Patent.

Patented Aug. 28, 1917.

Application filed July 6, 1914. Serial No. 849,088.

To all whom it may concern:

Be it known that I, MARK THOMAS DENNE, a subject of the King of Great Britain and Ireland, residing at Rushden, Northamptonshire, England, have invented new and useful Improvements in and Relating to Welt-Guides for Boot and Shoe Sewing Machines,- of which the following is a specification.

This invention has reference to improvements in and relating to welt guides for boot and shoe sewing machines and its main object is to enable the welt guide to be adjusted in accordance with orrelatively to the circular path of movement of the needle so that the needle will always pass through the welt at substantially the proper distance from its edge while permitting the welt guide and welt to be adjusted according -to variations in the substance or thiclmess of the work (for example at the toe portion the thickness of the work is almost invariably considerably increased).

I describe hereinafter means whereby the aforesaid object may be attained although I do not limit the scope of my invention thereto but at the same time I wish it to be understood that the particular means described also form an important feature of my invention.

In the accompanying drawings, Figure 1 illustrates in side elevation one embodiment of my invention;

Fig. 2 is a section on the line 22, Fig. 1. Fig. 3 is a section on the line 33, Fig. 1.

Fig. i is a detail showing the stop screw 0 Fig. 5 is a sectional view through the plunger.

In said drawing: a indicates a welt guide of suitable form, which I support in a cylindrical bifurcation 6 formed at the end of a welt guide bar a. The welt guide a is thus capable of pivotal movement in said bearing so that by meansfor exampleof a screw (Z and nut e the said guide may be adjusted up or down-according to the thickness of the particular kind of work to be operated onrelatively to the path f of movement or oscillation of the needle.

The welt guide when it is drawn back or moved forward relatively to a median point, and as is necessary accordingly as the particular portion of the work for the time being acted on is of increased or diminished thickness, should for a certain distance (more or less) depart as little as may in practice be conveniently possible from the path of oscillation of the needle. This is attained in the particular constructional form of my invention illustrated by imparting to the welt guide bar a compound movement, one rearwardly and the other upwardly so that the movement of the welt guide maintains its angular disposition to the horizontal.

The distance through which the welt guide should be made to move as aforesaid is usually about of an inch (more or less) and thereafter the guide should be made to move comparatively rapidly from the path of the needle-so as to insure its being clear of the needle guide and the stock of the needle carrier. 1

The mechanism now to be described attains these objects sufficiently accurately for practical purposes.

At the rear end of the. welt guide bar 0 I provide slide blocks 9 (which as shown are adapted tov move in a horizontal plane) and which slide blocks receive trunnions h of a rock bar 11 the latter being connected or engaged at its upper end with oneend of a suitably supported lever j to which movement at the proper times is imparted from a suitable part of the machine.

The front end of the welt guide bar 0 also has a pair of slide blocks or pins 7: adapted to move in guides Z which are angular to the slides 9. These guides Z operate to guide the front end of the Welt guide bar and give it a right line movement.

The lower end of the rocking bar 2' is bifurcated and engages a roller or the like m on the rear end of a rack bar n which latter has rack teeth 0.

Adapted to engage said rack teeth 0 is a toothed plunger 39 (having a compensating device to be described) which a spring 1 tends to raise out of such engagement. Normally the plunger 70 is held depressed by a disk or the like 1" but cam'parts or the like 8 permit its being raised at the proper times.

t is the usual crease guide and u is a spring which presses against the trunnions h or the guide blocks 9 to move the welt guide bar 0 forward when the toothed plunger p is raised out of engagement with the rack 0. o is the back rest which is carried at the front end of a rack bar to the forward movement of which rest is adjustably limited in any known suitable manner.

Located over said bar w is a lever a one end of which 1s rotatably mounted on a pivot 2 while its other or free end is connected bya link y to the lever Mounted on the pivot .2 is a pawl 00 or the like to which movement is imparted by the lever co in such a manner that as the lever j is swung forward or backward said pawl engages or disengages a rack to or the like of the rack bar to thereby either looking or releasing the back rest '0.

The before mentioned compensating device is provided to insure that the teeth on the plunger will correctly mesh with the teeth 0 on the rack bar a when said plunger is depressed by the action of the disk 7.

For this purpose the plunger consists of two parts 72 and p which-care normally forced apart by a spring 10 of small strength as compared with the spring g. The bottom face of the part is provided with teeth while its upper end is formed with a head capable of a limited longitudinal movement in a cut away portion of the upper part 22 The whole plunger is lifted by the spring 9. Should the teeth 0 not be at first in a position to correctly mesh with those in the part p when the plunger is depressed the compression of the spring 29 allows a short space of time to lapse, during which the rack bar may travel a short distance so that the teeth correctly mesh, before the teeth of the plunger are pressed firmly into engagement with those of the rack bar 1".

For the purpose of limiting the forward movement of the welt guide a and preventing its contacting with the channelor crease guide t, I provide an adjustable stop is, herein shown as a stop screw carried on any suitable part of the machine, and situated to limit the forward movement of the slide block or pin F0.

The operation of the hereinbefore de scribed mechanism is as follows :After a stitch has been formed the welt guide is moved rearward (a short distance'to allow of the work being fed) by the rearward movement of the bar 71 which as the rack bar a is locked by the plunger 19, is moved about the roller m as a fulcrum by the lever j. hen the feed has taken place the plunger is raised and the welt guide pushed forward by the spring a, this manner of moving the welt guide forward permits of the latter automatically adjusting itself according to the thickness of the work which as is well known varies at times considerably even from stitch to stitch; When the welt guide is forward and has contacted with or is pressing against the work the plunger again locks the rack bar nto thereby hold the welt guide firmly while the needle draws the loop of thread.

After the needle has reached its extreme rearward position; i. 6. when the thread has been drawn its tautest (and preferably even after the needle has again begun its return or forward movement) the plunger 29 again releases the rack bar n and thereupon the lever j moves to its original position caus ing therocking bar 2' to rock on its pivot h to thereby pull back the rack bar n to a position determined by or dependent upon the thickness for the time. being of the work, after which the plunger again locks said rack bar. After this the cycle of operations is repeated.

When the rack bar a is released the second time the said bar and also the welt guide bar 0 are quite freeand it is while the parts are in this position that work can be put in or removed. It is not necessary to re-lock the rack bar n and with it the welt guide a until the needlehaving passed through the welt and upperis about to return with the loop.

WVhat I claim as my invention and desire to secure by Letters Patent is 1. In a boot and shoe sewing machine, the combination with an oscillatory curved needle, of a welt guide, a movable welt guide bar by which the welt guide is fixedly sustained, means for giving reciprocating movement to said bar, and means for guiding the rear end of said bar for movement in a horizontal line and for guiding the front end of said bar for right line movement in a direction inclined to the horizontal whereby the welt guide is maintained in such a position relative to the needle path that the needle will always pass through the welt at substantially the correct distance from its edge notwithstanding variations in the thickness or substance of the work.

In a boot and shoe sewing machine, the vcombination with a welt guide bar having a bifurcated end, of a welt guide pivoted in said bifurcation, an adjusting screw pivoted to the welt guide and extending through an aperture in one arm of the bifurcated end of the welt guide bar, and an adjusting nut carried by said arm and engaging the adjusting screw whereby the welt guide can be adjusted relative to the welt guide bar but will be held rigid therewith in its adjusted position.

3. In a boot and shoe sewing machine, the combination with a spring-pressed welt guide bar, of a welt guide carried thereby, a rocker bar pivotally connected intermediate of its ends to the welt guide bar, a toothed bar connected to one end of the rocker bar, an actuating lever connected to the other end of said rocker bar, and means for periodically clamping said toothed bar in fixed position and then releasing it whereby the welt guide will be adjusted at each stitch into a position determined by the thickness of the work.

4t. In a boot and shoe sewing machine, the combination with a welt guide bar 0, of a welt guide carried thereby, a spring acting against the welt guide, a rocker bar 2' pivotally connected to the welt guide bar, a toothed bar a connected to one end of the rocker bar, means for rocking the rocker bar 2', a toothed plunger 19 adapted to engage the toothed portion of the bar end and lock it in position, and means for periodically placing said plunger in locking engagement with the bar end and then releasing said plunger.

In a boot and shoe sewing machine,

the combination with a welt guide, of an oscillating lever by which the welt guide is actuated, a back rest, a toothed bar by which the back rest is carried, a locking pawl for engaging said toothed bar and locking the back rest in position, and means connecting said pawl with said oscillating lever whereby the back rest is locked and unlocked in timed relation with the operations of the welt guide.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

MARK THOMAS DENNE.

Witnesses;

VVALTER WV. BALL, F. H001).

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

